Hydraulic feeding unit



Nov. 6, 1956 J. GRATZMULLER 2,769,399

HYDRAULIC FEEDING, UNIT Filed Oct. '4, 1951 -5Sheets-Sheet 1 Nov. 6, 1956 J. L. GRATZMULLER 2,759,399

HYDRAULIC FEEDING UNIT Filed Oct. 4, 1951 f 5 Sheets-Sheet 5 K Hg4 Httorhe as 1956 J. L. GRATZMULLER 2,769,399

HYDRAULIC FEEDING UNIT Filed Oct. 4, 1951 5 Sheets-Sheet 4 FIG. 5

A-Irarneys Nov. 6, 1956 J. L, GRATZMULLER 2,769,399

HYDRAULIC FEEDING UNIT Filed Oct. 4, 1951 5 Shee'tsSheet 5 t ll 1 W I 6333W-*W fittorneys United States Patent I Oflice latented Nov. 6, 1956 HYDRAULIC FEEDING UNIT Jean Louis Gratzmuller, Paris, France Application October 4, 1951, Serial No. 249,748

Claims priority, application France October 9, 1950 2 Claims. (Cl. 103-423) This invention relates to fluid energy storage systems adapted to transmit the stored energy to a fluid operated device such as a hydraulic motor or a fluid pressure cylinder having a piston therein, and which will be hereinafter termed hydraulic jack.

Such systems usually comprise a number of elements such as a reservoir, a pump connected to the reservoir to draw liquid therefrom, a hydraulic-pneumatic accumulator to store the liquid delivered by the pump at a predetermined pressure, control valves and so on. This implies necessarily a great number of conduits to interconnect said different elements.

The broad object of the invention is to provide a hydraulic energy storage system of the type referred to comprising an assembly block adapted to receive and to complete the casings of the different elements constituting an energy storage system of the aforesaid type, said assembling block being provided with all passages required to ensure the interconnection of said elements, as well as the connection of the energy storage system with a fluid operated device to which the stored energy has to be transmitted.

The assembling block of the energy storage system according to the invention comprises a number of individual portions such as housings, apertured wall portions and the like, designed to receive corresponding portions of each of the aforesaid elements, said housings and the like thus constituting a part of the casings of said elements, separate complementary members especially designed being provided to cooperate, when mounted on the block, with said housings and the like to complete the casings.

The invention thus makes it possible to provide a hydraulic energy storage system comprising, in one compact and self-contained unit, a number of elements which heretofore constituted a cumbersome and complicated plant.

Moreover, the hydraulic energy storage unit according to the invention permits eliminating all assembling and securing means, except for securing said unit to a suitable stationary part, as well as all tubes, except for that or those necessary to ensure the feeding of afluid operated device and the return of the liquid into the unit, according to whether said fluid operated device is a hydraulic jack or a hydraulic motor.

Another object of the invention is to provide a hydraulic feeding unit of the type described in which all elements liable to leak are located inside the tank and immersed in the liquid of the same.

The hydraulic feeding unit according to the invention is particularly, but not exclusively, adapted to be used in combination with engine starters or with electric circuit breakers actuated through one or more hydraulic 'ja-cks or the like. I

Other objects and advantages of the invention will be apparent from the following detailed description, together with the accompanying drawings, submitted for purposes of illustration only and not intended to define the scope of the invention, reference being had for that purpose to the subjoined claims.

In these drawings:

Fig. 1 is a front elevational partly sectional view. with parts broken away of a hydraulic feeding unit according to the invention. I r

Fig. la is an enlarged detail view illustrative of the manner in which one part of the hydraulic energy storage unit shown in Fig. 1 may be sealed in respect to another part thereof.

Fig. 2 is a top view of the unit shown in Fig. 1.

Fig. 3 is a partial section along axis 3--3 of Fig. 2 showing in particular the inside of the casing, the tank,

the supporting block, the control lever and the pump.

Fig. 4 is a vertical section along line 4.4 of Fig. 2 showing in particular the details of the relay valve and pressure indicator.

Fig. 5 is a vertical section along line 5-5 of Fig. 2 showing the pump and the safety valve, in particular the yoke and lever of the pump.

Fig. 5a is an enlarged detail view of the connecting means between the two piston rod portions of the pump shown in Fig. 5.

7 Figs. 6 to 9 show various positions of the sliding member of the relay valve, and

Fig. 10 shows two right-angled views of a detail of said sliding member.

Referring to the drawings, there is shown at A a hydraulic-pneurnatic accumulator, at B a casing acting as a tank and at C the supporting block of the unit. Accumulator A isscre'wed into a threaded cylindrical hole provided in the lower face (referring to Fig. l) of the supporting block C, while casing B is mounted onthe upper face of said supporting block through a lip 21 (Fig. 5) with interposition of a packing device 22, said casing being secured on said supporting block by means of a number of bolts M (Fig. 2) screwed in threaded holes provided in th upper face of supporting block C.

on the top surface of casing B is disposed the lever I of a pump D, said lever being mounted in a yoke I articulated on casing B around an axle 23. The pump D proper is mounted within casing B, the lower end of said pump being screwed intoa threaded hole provided in the upper face of supporting block C. Said pump may be of any type and, in particular, of a suitable known type. In the example shown (Fig. 5), the piston of the pump is made of two rods 2425 between which is interposed a ball 26, the opposed end faces of rods 24, 25 being provide with suitable recesses to house said ball. This arrangement avoids the necessity of locating the rods in an accurately aligned position, which eliminates all risk of jamming, while permitting a slight oscillation of rod 25 with respect to the straight moving rod 24 as yoke I is rotated around axle 23. The two rods 24, 25 are linked with one another (Fig. 5a) through connecting straps 27 and gudgeon pins 28. When lever J is rotated clockwise around the axle 23 of yoke I (Fig. 5), the liquid contained in tank B is sucked through a filter 60 and through opening N of easing B into the pump, while, when said lever is rotated counter-clockwise, said liquid is forced through a passage 29 and a non-return valve 30 into the upper space of accumulator A.

There is shown at F a safety valve controlling passage 29 and the spring 31 of which is so calibrated that, when the pressure in the accumulator reaches a predetermined value, the liquid forced out through passage 29 under the action of pump D, instead of being fed into the accumulator, escapes through openings 32 into casing B, since ball 33 is then lifted off its seat.

7 Passage 29 is drilled from one side of the supporting block and is obturated by means of a threaded plug R. The inner threading into which plug R is screwed may be used alternatively to receive, instead of said plug, a tube union permitting to use, beside pump D, any additional mechanical pump.

The upper space of the tank-casing B communicates with atmosphere through a duct H provided with a filter 34. This is to prevent any risk due to over-pressure in the tank. The outlet of said duct H is directed downwards so as to avoid any splash.

An accumulator A having a generally cylindrical shape andadapted to be screwed as a whole by its upper end (Fig. 1) in the supporting block C is preferably used. In the example shown, said accumulator is of the type described in U. S. application Serial No. 247,226, filed September 19, 1951, now Patent No. 2,724,412, which permits accumulating the required power under a reduced volume in a container constituted by a simple tube.

Accumulator A is filled through an opening 35 with compressed air, e. g. at 200 kg./ 01:11. said air is then compressed by liquid such as oil admitted into the accumulator under the action of pump D at a pressure of e. g. 300 kg./cm. whereupon the device is ready to work.

The value of the pressure in the accumulator is preferably displayed on a pressure indicator of a suitable type communicating with the upper space of the accumulator in which is located the pressure oil. Inthe example shown, said indicator, shown at G, is of the type described in the U. S. patent application filed by same applicant under Serial No. 235,759 of July 7, 1951, for: Fluid Pressure Indicator, now Patent No. 2,597,724, May 20,

The threaded opening P on which is mounted the pressure indicator G may be used also'for mounting in parallel with accumulator A an auxiliary accumulator, in

order to increase the output of the apparatus. The threading of the elbow screwed into the opening is preferably slightly conical to facilitate the mounting of the pressure indicator.

In order to obtain easily the required tightness between accumulator A and the supporting block C, the upper portion of the wall of accumulator A is preferably bored with a threaded hole 36 into which is screwed a screw 37 pressing a lead pad 38 against the threading 39 of accumulator A. This lead pad, when crushed under the screwing action of screw 37 suppresses any leakage along the thread. This device is shown in detail in Fig. In. To control the evacuation of the pressure liquid contained in accumulator A towards the prime mover to be fed, which communicates with said supporting block as shown at Q, the unit also comprises a relay valve E. Said relay valve E preferably includes two essential parts. The first one is constituted by a set of movable valve means located (Fig. 4) in the lower portion of the valve unit E and the second one is a servo-mechanism located in the upper portion of the valve unit E. The above mentioned valve means comprise a main valve 1 the opening of which determines the flow of the whole mass of the pressure liquid of accumulator A towards outlet Q. Valve 1 is urged towards its seat 64 by means of a spring 61 the guiding and abutting of which are ensured by a mushroom 62 held by a cross rod 63. The body of relay valve E is screwed into the supporting block C. During this operation, said valve body comes into contact with a conical .surface provided on seat 64, which results in slightly enhoused in a bore of valve 1 and having a seat 4a and by a rod 5 capable, in a well-defined axial position, to separate said ball'from its seat. Rod 5 is fast with a head 43 fit with a clearance in a bore 41) provided in the upper end of the main valve 1. When the control push-button K of the relay valve is pressed upon, a valve assembly is actuated in a manner described herein, so as to push through head 43 and rod 5 the ball 4 from its seat, thus opening first the passage extending from accumulator A to bore 40 so that the liquid under pressure from the accumulator will flow through a lateral hole 7 and the annular space 41 and passage 42 towards outlet Q.

The valve assembly 2-3 is constructed and arranged in such a manner that it permits the liquid which has been conducted to the motor through its outlet Q to return from the motor into the tank B via the same outlet Q, a passage 42, an annular space 43, the bore 51, and the openings 52 and 53, and this as long as the valve assembly 23 is in its open position.

The rate of flow of the pressure liquid from accumulator A is limited through a calibrated hole 6 provided in a disk obturating the bore of valve 1.

As soon as rod 5 has been sufiiciently displaced downwards (Fig. 4), the bottom 44 of bore 40 is obturated. From the very moment when the head 43 comes into contact with shoulder 44, the valve 1 is urged downwards, opens and lets the whole mass of liquid contained in the accumulator escape through outlet Q.

It will be easily understood that due to the high value of the fluid pressure in accumulator A, the force which has to be exerted upon the push-button would be too considerable to allow manual operation of the latter.

In order to reduce the force to be applied upon pushbutton K'to act upon the valves, there is provided a servo-mechanism or relay using the very pressure of the accumulator to ensure the displacement of valve 1. Said servo-rnechanism is essentially constituted by a piston 10 adapted to receive on its upper face, through a pipe L, the pressure of the upper space of accumulator A. Since the area of piston 10 which is acted upon by said pressure is greater than the area of valve 1, it will be easily understood that, as soon as said pressure is free to act upon piston 10, said valve 1 will be immediately opened, and this without requiring any stress from the operator.

To control the admission of the pressure towards the upper surface of piston 10, as well as its return into the tank, a specially designed distributor 12 is provided.

Before describing said distributor, it is pointed out that the tightness at the upper end of cylinder 45 of the body of relay valve E is ensured by a packing Washer 14 and by a nut 15. A spring 13 ensures, through a rigid Washer 46 and a plastic or elastic washer pressed upon by said washer 46, the tightness at the top of casing B.

Distributor 12 shown in details in Figs. 6 to 10 comprises an axial passage 2020a20b with which communicate passages 46 ensuring the return of liquid to tank B, radial passages 47 communicating through one or more ducts 48 with the space of the cylinder located above piston 10 and radial passages 49 also communicating with passages 48 and adapted to be put into communication with passages 46 through the upper portion of the axial passage 20. Said axial passage comprises three sections of various diameters. The upper section 21) extends down to radial passages 49 and is followed downwards by a section 20a having a larger diameter and extending downwards further than radial passages 47, said section 2011 being followed in turn by a section 20b having a still larger diameter and the upper end of which constitutes a seat for a ball 18. Ball 18 cooperates with said seat to constitute an admission valve.

In the axial passage 20 is slidably mounted a rod 16 adapted with atight fit in said passage and acting as an bers of the distributor rest in the position shown in Fig. 9,

said positionbeing assumed under the very action of gravity. As soon as pump D is acted upon and begins to build up a certain pressure in the accumulator, ball 18 is urged upwards since said pressure is sent under said ball through pipe L. The movable members of the distributor are then brought into the position shown in Fig. 6. Ball 18 is seated and prevents the pressure from passing through axial passage 20a.

When the push-button K is pressed upon, the movable assembly 16-1917-18 is displaced downwards and brought into the position shown in Fig. 7. In this position, ball 18 is lifted off its seat, passage 20 is further closed by rod 16 and the pressure liquid incoming through passage 20]) is sent through passage 20a, radial passages 4749 and ducts 48 into the upper space of cylinder 45. The pressure liquid cannot escape through passage 20 and radial passages 46 for, as mentioned above, rod 16 is adapted with a tight fit in passages 20. Piston is thus subjected to the whole pressure of the upper space of the accumulator and the movable members of the valves described above which are located in the lower portion of device E are displaced as previously described. After a predetermined time, the liquid which has been sent into valve body E fed through pipe L should be brought back into tank 13. For this purpose, the communication between the valve body E and the pipe L should be interrupted, while the communication between the part of valve body E fed through pipe L and tank B should be simultaneously established. The position of the movable members of the distributor during the return of the liquid towards the tank is shown in Fig. 8. As soon as the push-button K is released, spring 11 urges said button back into its original position, so as to release rod 16. The pressure which is admitted, as shown by the arrow of Fig. 8, into duct 48, passes through radial passages 47-49 into the axial passage a and acts upon the lower end of rod 16 which is thus displaced upwards. As shown in Fig. 10, ball 19 can never obstruct passage 20, so that the pressure of the liquid is free to act upon rod 16 so as to let the same slide upwards until it has assumed the position of Fig. 8 in which it opens the passages 46 through which the liquid then freely flows towards tank B. As soon as the evacuation is finished, the movable members once more assume the position of Fig. 9 until liquid is fed into the accumulator anew, and so on.

It is to be pointed out that the distributor which has been just described eliminates any possibility of a direct leakage from accumulator A into tank B, While being exceedingly simple and cheap to construct, since it is merely constituted by two straight rods and two balls. Moreover, the stroke of the push-button is reduced to a minimum due to the interposition of rod 17 and ball 19, and is equal to the sum of the length of the axial passage 20 :and the distance through which the ball 18 is lifted off its seat.

Furthermore, since the cross-section of rod 16 is smaller than the cross-section of passage 20a, the stress to be exerted upon the push-button K to maintain the sliding member and the valve of the distributor in the position shown in Fig. 7 is weaker than the stress which has been necessary to bring the same into said position.

It is to be understood that any system of three-way push-button may be used instead of that which has just been described within the scope of the invention.

While the invention has been described with particular reference to a preferred embodiment, it is not intended to limit the scope of the invention to the embodiment illustrated, nor otherwise than by the terms of the subjoined claims.

What is claimed is:

1. A hydraulic energy storage unit comprising, in combination with a plurality of cooperating elements adapted to store liquid pressure and to deliver said stored liquid pressure, an assembling block for said elements having a lower end portion recessed to receive one of said elements and an upper horizontal surface provided with at least two vertical holes each adapted to receive one of two others of said elements, said elements including a liquid storage reservoir having a cylindrical side wall the lower end portion of which is joined to said upper surface so as to encircle said holes thereof, said upper surface thus constituting the bottom of said reservoir, a reciprocating pump comprising a tubular casing housed in one of said two holes so as to have its lower end closed by the bottom portion of said one hole and having inlet means opening in said reservoir, a control valve mechanism comprising a tubular casing housed in the other hole so as to have its lower end closed by the bottom portion of said other hole, and a hydro-pneumatic accumulator comprising a pressure vessel'having a movable partition therein dividing the vessel into a closed gas pressure chamber and an open ended liquid pressure chamber inserted in said recessed lower end portion of the assembling block so as to be tightly closed thereby, said assembling block further being provided with passageways interconnecting said lower end portion with each of said holes to conduct the liquid drawn by said pump from said reservoir to the liquid pressure chamber of said accumulator and the liquid stored by the latter at a predetermined pressure to said control valve mechanism, respectively, and an outlet duct leading from said other hole to the outside of said block, said valve mechanism being adapted to control the delivery of stored pressure liquid from said accumulator to said outlet duct.

2. A unit according to claim 1 in which the assembling block is provided with an additional hole communicating with said passageway-s, said unit including an additional hydro-pneumatic accumulator mounted in said additional hole and the connection of said additional hole to said passageways being such that said additional accumulator is connected in parallel with the first named accumulator.

References Cited in the file of this patent UNITED STATES PATENTS 547,221 Mann Oct. 1, 1895 958,853 Bulley May 24, 1910 1,191,469 Rixen July 18, 1916 1,468,604 Mayer Sept. 18, 1923 1,787,751 Mathewson Jan. 6, 1931 2,492,014 Spalding et al. Dec. 20, 1949 2,622,400 Greer Dec. 23. 1952 FOREIGN PATENTS 414,798 Great Britain Aug. 16, 1934 

